GRANT=6446816;P01AG The major goal of the Core is to provide support for subprojects: These services will include the following: metabolic studies (euglycemic and hyperglycemic glucose clamps,, tracer turnover studies), regional and tody body composition, muscle histological and cytosine analysis, muscle formation, functional status, resulting energy expenditure, and relevant study questionnaires. In addition, oversight of the Data Safety and Monitoring board is the responsibility of the Core. The Core will apply standardized methods with quality assurance mechanisms to maximize data quality and minimize methodological variation and measurement drift. The centralized organization will ensure financial stability, expert quality control and availability of services to all study investigators. The core will be responsible for providing the statistical analyses that are required. The tests performed by this Core are ones that are well established at the Massachusetts General Hospital and the Nutrition, Exercise Physiology, and Sarcopenia (NEPS) and Body Composition Laboratories at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. Thus, there is a wealth of experience on the part of the investigators in uses and limitations of these methods. Opportunities to learn methodological procedures and techniques operation in the core will be available to postdoctoral and junior faculty interested in Clinical research.